Grafting Continues...

Larix grafts

The prior Flora Wonder Blog discussed the beginning of our winter grafting season, where we graft the relatively easy warm-up conifers such as Metasequoia and Larix. In neither case do we paint a tree-seal on the graft unions, nor do we place the finished grafts in a thin-poly sweat tent. These easy-to-produce deciduous conifers do not need any extra fussing, therefore we keep the process simple.

Cedrus grafting in progress

Cedrus grafts

Our next grafts are various Cedrus cultivars, and for those we do place them in a poly tent which seems to improve “graft takes.” Generally, if the scionwood is decent, we expect an 85-95% take with Cedrus deodara as rootstock (a two-year seedling plus one year in a pot). The Cedrus are our first “cover-up” crop because they'll be the first we uncover, the reason being that the rootstocks and scions flush new growth before the spruces, pines etc. If left in a too wet and humid situation the new growth can quickly experience an outbreak of botrytis, a mold that can devastate new growth on the scions. I learned this mistake with my first crop of Cedrus atlantica 'Glauca' where I custom grafted 16,436 plants for another company in their greenhouse. They were placed on bottom heat and the graft unions were buried in sawdust, and to top it off, the foliage was water-misted three or four times a day. What began as a 95% graft take – beginner's luck I guess – devolved to about 60% once the moldy parts were pruned and a fungicide was applied. I was only paid for the final, successful result, not for how many I attempted. That experience was my introduction to “real-world” horticulture which has continued to this day. Nobody cared how hard I worked or how much money I invested or how stressed I became...only caring about what I had for sale. Real world indeed – just get bottom-lined used to it.

Cedrus brevifolia 'Kenwith'

Cedrus brevifolia 'Kenwith'

Cedrus brevifolia 'Kenwith'

Most authorities recognize four species in the true Cedrus genus: atlantica, libani, deodara and brevifolia, with the latter (from Cyprus) being the least hardy (USDA zone 7). Nevertheless we produce C. brevifolia 'Kenwith' by grafting onto C. deodara rootstock and the cute conifer thrives in our gardens, and can be marketed on the West Coast at least. 'Kenwith's' charm is that it resembles a full-sized, upright tree and yet only grows a few inches per year. It looks like a well-cared-for bonsai, but the gardener never needs to attend to it. We can thank Gordon Haddow of Kenwith Castle Nursery, Devon, UK for the introduction.

Cedrus atlantica 'Glauca'

Cedrus atlantica 'Silberspitz'

I used to grow thousands of Cedrus atlantica per year, mainly 'Glauca' and 'Glauca Pendula', but haven't produced either of those two in the past twenty years. They became too common and their value declined; when you see them offered at the box stores' garden centers you know it's time to discontinue. A few weeks ago we grafted Cedrus atlantica 'Silberspitz', a relatively new introduction from Horstmann's Nursery in Germany. Its growth habit is similar to the well-known C.a. 'Glauca' – fast-growing and narrow when young – but 'Silberspitz' features cream-white new growth at the branch tips, and the colorful shoots contrast nicely with the older blue-green foliage. The name translates to “silver pointed” in German, and it looks best in our field in spring; in winter the silver transforms to a burnished yellow which is a bit less spectacular. A cautionary note is that the gardener is wont to plant 'Silberspitz' too close to the house, or in a tight garden spot due to its narrow form when young, but at maturity, it will become quite large with a broad canopy, so give it ample space.

Cedrus atlantica 'Sahara Ice'

Another “Atlas cedar” with a similar form is 'Sahara Ice' but it differs from 'Silberspitz' in that the needle tips are white, not the new shoots. In my opinion 'Sahara Ice' is the more glitzy of the two, and more colorful throughout the year. We have a well-established tree in our Conifer Field that withstood our 116 F heat dome a couple of years ago without any burn. The downside with the faster Cedrus atlantica cultivars is that they stretch out in our growing conditions, where a three-foot tree in a one-gallon pot might only be pencil size in caliper at the base. The employees look at me like I'm crazy when I instruct them to cut the trees in half and retrain a new leader, but it's bad form to sell a non-weeping tree that requires a stake. 'Sahara Ice' was discovered and introduced by the late Bill Janssen of Washington state, a plantsman with a penchant for variegated conifers. I once teased him that even his weeds must be variegated.

Cedrus atlantica 'Blue Cascade'

Cedrus atlantica 'Blue Cascade'

A cultivar that we do stake is Cedrus atlantica 'Blue Cascade', an aggressive weeper whose foliage is more silvery-blue than the old standby C.a. 'Glauca Pendula'. We stake our 'Blue Cascade' to about six feet tall, then top the leader so it will spill out evenly. In ten years the six-foot whip will mound to about eight feet tall by ten feet wide, with much more growth yet to come, so it's not suitable for the smaller garden. My oldest specimen is growing at Flora Farm, and many times when I approach it a squirrel runs into, or out from the blue haystack.

Cedrus atlantica 'Sapphire Nymph'

Cedrus atlantica 'Sapphire Nymph'

More manageable for the small garden is the dwarf Cedrus atlantica 'Sapphire Nymph', a spreading form with silver-blue needles smaller than the type. It can also be staked up into a pyramidal shape, but in either case it is most dazzling when grown in full sun with good drainage. I don't know the origin of 'Sapphire Nymph' – except that it was introduced by Pat McCracken of Tennessee. I mean that I don't know if it was a random dwarf seedling, or if it derived from a witch's broom mutation. I suspect the latter is the case because I've experienced a couple of specimens that appeared to revert to the more vigorous growth of the type.

Cedrus atlantica 'Blue Haze'

Cedrus atlantica 'Blue Haze'

'Blue Haze' is more dwarf than all the aforementioned Cedrus atlantica cultivars, and it definitely originated as a witch's broom. Our oldest, 20-year-old specimen is growing in the Blue Forest section and is about 5' tall by 6' wide; this is the first year we have decided to propagate what began as a one-gallon potted gift. We haven't trained or pruned our stock tree, but I suppose that it will eventually produce a leader. Its foliage is also silver-blue, and as with its 'Sapphire Nymph' sister, both selections require full sun in well-drained soil to display best sparkling color.

Atlas

Atlas Mountains, Northern Africa

I began the Cedrus discussion by listing four species that comprise the Cedrus genus, however, some authorities place C. atlantica as a geographical variety or a sub-species of C. libani. Both libani and atlantica are of mountainous origin with the latter from the Atlas Mountains of northern Africa, a range that separates the Sahara Desert from the Mediterranean Sea. In Greek mythology Atlas was a Titan condemned to hold up the heavens for eternity, but he was also admired for his understanding of mathematics and astronomy, and perhaps he was the inventor of the first celestial sphere. In more modern times the term atlas describes a collection of maps, coined in the 16^th century when geographer Gerardus Mercator published his work in honor of the mythological figure, and the Atlantic Ocean is of course the “Sea of Atlas.”

Cedrus deodara

Cedrus deodara

Cedrus deodara 'Feelin' Blue'

Cedrus 'Harvest Gold'

Cedrus deodara 'Limeglow'

Cedrus deodara 'Silver Mist'

Cedrus deodara 'Silver Mist'

I have been fortunate to see Cedrus deodara in the wild – impressive, big gnarly monsters at 8,000 ft. in the Himalayan foothills. The specific name is derived from Sanskrit devadaru which means “wood of the gods,” while the word Himalaya means “abode of the gods.” We have grown a large number of C. deodara cultivars which were selected primarily for the blueness of the foliage and also for cold tolerance (to -18F). Due to our limited number of rootstocks this season, we only grafted four cultivars: C.d. 'Feelin Blue', 'Harvest Gold', 'Limeglow' and 'Silver Mist'. The first three are weepers, one gray-blue and two cream-yellow, and you can figure out the colors based on their name. C.d. 'Silver Mist' is also apropos for the dwarf pyramidal selection with whitish needles that can be grown in full sun in most Oregon summers. 'Silver Mist' was introduced in the mid 1960s by the noted conifer plantsman William Goddard of Flora Vista Gardens, Victoria, B.C., Canada. In the past we grew a couple of deodara cultivars similar to 'Silver Mist' – 'White Imp' and 'Snow Sprite' – but they weren't quite as strong or sun tolerant. My evaluation is based upon personal experience and from observing rows of 'Silver Mist', 'White Imp' and 'Snow Sprite' growing next to each other at the old Redwood Lane Nursery, Willamette Valley, Oregon. Most growers of these three dwarves will assign rates of growth – say, 5' tall by 4' wide in 10 years for 'Silver Mist' – based upon grafts of the cultivar onto vigorous, seedling deodara rootstock. However, all Cedrus deodara cultivars can be grown from rooted cuttings, where growth rates will be significantly reduced.

Chamaecyparis (Xanthocyparis, Callitropsis) vietnamensis

Chamaecyparis (Xanthocyparis, Callitropsis) vietnamensis

Thuja orientalis 'Van Hoey Smith'

We will graft more “cedars” later this winter. These are not from the true Cedrus genus, but rather various conifers that are commonly referred to as “cedars,” such as Thuja (Platycladus) orientalis, Thuja occidentalis, Thuja plicata, Chamaecyparis (Xanthocyparis, Calitropsis) nootkatensis and vietnamensis, and Calocedrus decurrens. So many cedars!, too many when they're commonly reduced in scientific nomenclature, and where the serious nurseryman must find the best, most compatible rootstocks for production. We keep records of all rootstock/scion combinations so we remember what succeeds and what flounders or what fails outright, and when I sold my company to Mr Maple a few months ago, that record was one of the most important assets that they acquired.

Grafting conifers

We will graft these miscellaneous “cedars” in a couple of weeks, as the rootstock is currently warming with increased temperature and longer day-length in our Greenhouse 12 propagation facility. When the roots reach their estrous stage we will copulate them – as the Euros say – with selected cultivars, and hopefully we will produce little babies to grow on for future sales. I have never been one to hold propagation “secrets” closely, preferring a reciprocal relationship with other growers so we can both learn and advance our businesses. How else could this botanical simpleton ever have completed a successful career in horticulture...without the guidance and generosity given freely by other growers? Basically, my plant blogs are thank-you notes to my peers, to those who have come before me and for any who care to follow. If my observations and suggestions seem vague at times, it is because I'm still a relative beginner myself. Old-man Buchholz – ever a student.